The present invention generally relates to balloon dilatation catheters, and, more particularly, to a balloon catheter having a plurality of lumens one of which contains a one-way valve permitting fluid flow in one direction and preventing fluid flow in the other direction.
Balloon dilatation catheters are used for a variety of procedures in which a body lumen or vessel is dilated. For example, such catheters are used in percutaneous transluminal angioplasty procedures in which a stenosed region of an artery, such as a coronary artery, is widened by inserting a deflated balloon into the stenosis and then inflating the balloon under pressure to forcibly enlarge the lumen through the artery. After a brief period of time, the balloon is deflated and removed. Such catheters typically have an elongate flexible shaft and a balloon mounted at the distal end of the shaft. The shaft has a balloon inflation lumen that communicates from the proximal end of the catheter to the interior of the balloon at the distal end of the shaft. The catheter also has a guidewire lumen that extends fully the length of the catheter shaft, terminating in a distal outlet at the distal tip of the shaft, beyond the balloon. The guidewire lumen may be used to receive a guidewire as well as to provide fluid communication with the interior of the patient's artery to inject radiopaque dye into the artery to visualize it fluoroscopically or to monitor the pressure in the artery, distally of the stenosis. Typically, the balloon is inflated with a liquid which is radiopaque so that the configuration and action of the balloon may be monitored fluoroscopically during the angioplasty procedure. Use of an incompressible liquid as an inflation medium assures effective development and transmission of dilating forces to the balloon and to the stenosed region of the artery that is to be dilated.
Since the balloon is used in arteries and veins, an inflation media must be selected which will avoid serious injury to the patient should the media be accidentally released into the body, e.g., upon rupture of the balloon. Because air and other gases are not quickly absorbed by the blood, they are particularly dangerous. Thus, radiopaque contrast media, either 100% or in solution with water of saline, is typically employed to fill and purge the balloon of all harmful gases. Air removal is essential not only to insure the safety of the patient but also to prevent air blocks which could limit the amount of expansion of the balloon, thereby reducing the effectiveness of the angioplasty procedure.
As a result of the foregoing dangers, various purging systems have been developed, wherein air is purged from the balloon and lumen with the subsequent insertion of radiopaque material.
One type of prior device/system is disclosed in the U.S. Pat. No. 4,323,071 to Simpson et al., which uses an arrangement where a vent tube is inserted through the balloon inflation lumen and into the balloon. When the purging liquid is introduced through the balloon inflation lumen, the air within the balloon is vented to the atmosphere from the vent tube. However, with this arrangement there is a possibility that inserting the vent tube into the flexible balloon could damage the balloon, creating leaks which may be unnoticeable. Further, this system for purging air from the catheter is somewhat time consuming and may be awkward in that it requires a number of manipulations of the vent tube. Additionally, there is some risk that the vent tube may damage the balloon. A further difficulty is that if a minute drop of liquid contacts the distal tip of the vent tube before purging is completed, the tube will become blocked by capillary action and may have to be replaced. Lastly, it may be desirable to increase the size of the lumen, requiring changing of the vent tube, which can also be a time consuming and difficult procedure.
Another type of purging device is disclosed in U.S. Pat. No. 4,545,390 to Leary, where a catheter is first evacuated by a syringe connected to the inflation lumen at the proximal end of the catheter. After air has been evacuated from the balloon, the inflation lumen and balloon are filled, by the syringe, with inflation liquid. Typically, one or more bubbles of air will remain entrapped in the balloon and, in an effort to purge as much air from the system as possible, it is the common practice to fill the balloon while holding the catheter with its distal end hanging down to permit the air to rise through the inflation lumen to the proximal end of the catheter where it may escape to atmosphere from the vented proximal end of the inflation lumen. Most, but not all of the air can be removed by this procedure. Usually, a small bubble of air will remain in the system.
Another form of purging device/method is described in U.S. Pat. No. 4,684,363 to Ari. This patent discloses a balloon dilatation catheter having a pair of parallel inflation lumens both of which extend from the proximal end of the catheter through the catheter shaft into communication with the interior of the balloon. The catheter is filled with inflation liquid by directing the liquid through one of the inflation lumens into the balloon while permitting the other lumen to vent to the atmosphere to permit air to escape. After both inflation lumens and the balloon are filled with inflation liquid, both of the lumens are connected to the inflation/deflation device and are operated in parallel to inflate or deflate the balloon. This approach requires the use of an additional lumen, which necessarily requires either that the catheter be increased in outer diameter or that the other lumens in the catheter be smaller in size, thereby diminishing their capacity. Additionally, such a three lumen catheter is more difficult to extrude, particularly in the smaller sizes of such catheters. Further, this structure and/or method is somewhat cumbersome and time-consuming, and requires a relatively high degree of skill to use successfully.
Another multi-lumen balloon catheter used for purging is described in U.S. Pat. No. 4,793,351 to Landsman et al. This patent includes a manifold having a valve connected to the proximal ends of the balloon and vent lumens and an inflation/ deflation device. The valve is adapted to have several positions to permit purging of the air to the atmosphere as the catheter is filled with inflation fluid. In another position the balloon is directly connected to vent lumens, which inflate and deflate the balloon. This device requires that the valve in the manifold be manipulated from the described position.
Applicant's U.S. Ser. No. 07/303,647 discloses a Fast Purge Balloon Dilatation Catheter with a slit on the catheter shaft within the balloon, which permits fluid flow from the guidewire lumen into the balloon. The slit operates as a one-way valve and is initially covered by elastic, which opens as the pressure increases, such as where a tip occluder is inserted into the distal opening of the guidewire lumen and contrast is injected down the guidewire lumen and into the balloon. Air trapped within the balloon is then vented out the balloon lumen. Although the above catheter offers many advantages over prior catheter purging devices, the present invention describes an improved catheter purging device.
There is, therefore, a need for a purging catheter device capable of being prepared from a position outside the body for use within the body, particularly for use in percutaneous transluminal coronary angioplasty in a simple and time-saving manner that does not require excessive manipulation of parts and elements associated therewith.
It is therefore an object of this invention to provide a new or improved angioplasty catheter.
Another object of this invention is to provide a new and improved angioplasty catheter device which is constructed to reduce the time required for preparing the device for use.
A further object of this invention is to provide a new and improved angioplasty catheter device which reduces the number of manipulative steps needed to prepare the catheter for purging air from the balloon and associated lumen in preparation for use.
Another object of the invention is to provide a new and improved angioplasty catheter which can have the air removed from the balloon and associated lumens and inflation fluid provided therein in a simple manner which does not require any additional training.
A still further object of this invention is to provide a new and improved balloon catheter device which permits more complete removal of air from the balloon than has been possible heretofore.
A still further object of this invention is to provide a new and improved balloon catheter device that does not require a tip occluder which may damage the tip.
Another object of this invention is to provide a new and improved balloon catheter that does not require additional flushing of the distal lumen after purging of the balloon.
Still another object of this invention to provide a balloon catheter device wherein a prolonged vacuum can be placed in the balloon without danger of aspirating air into the system.
Another further object of this invention is to provide a new and improved balloon catheter device wherein the catheter does not vent air to the atmosphere and wherein air within said balloon is directed to an inflation/deflation device.
The foregoing specific objects and advantages of the invention are illustrative of those which can be achieved by the present invention and are not intended to be exhaustive or limiting of the possible advantages which can be realized. Thus, these and other objects and advantages of the invention will be apparent from the description herein or can be learned from practicing the invention, both as embodied herein or as modified in view of any variations which may be apparent to those skilled in the art. Accordingly, the present invention resides in the novel parts, constructions, arrangements, combinations and improvements herein shown and described.